As a new input device, compared to conventional display panels, touch display panels have advantages such as being easier to use, having shorter response time, and being space-saving. Touch display panels are currently regarded as the simplest, the most convenient, and the most natural human-computer interaction means. The application of touch display panels are not limited to small portable electronic device. Instead, touch display panels are incorporated in more and more large-sized display devices.
When a large-sized display device is displaying images to a user from afar, it is often required that the display panel of the large-sized display device has a certain level of brightness. When the user is operating the display panel from a short distance, the undesirably high brightness of the large-sized display panel can be harmful to the user's vision. Conventional display panels are usually not able to automatically adjust its brightness level in accordance with the user's distance to the display panel. As a result, it can be tedious and time-consuming to change the brightness levels of a display panel using a remote control device or device buttons.